m6A profile in cardiomyocytes

To determine the role of m6A methylation in the heart we isolated primary cardiomyocytes and performed m6A immunoprecipitation followed by RNA sequencing. We measured the level of m6A methylation on cardiomyocyte mRNA, and found a significant increase in response to hypertrophic stimulation, suggesting a potential role for m6A methylation in the development of cardiomyocyte hypertrophy. Analysis of m6A methylation showed significant enrichment in genes that regulate kinases and intracellular signaling pathways. Inhibition of METTL3 completely abrogated the ability of cardiomyocytes to undergo hypertrophy when stimulated to grow, while increased expression of the m6A RNA methylase METTL3 was sufficient to promote cardiomyocyte hypertrophy both in vitro and in vivo. Our study identified METTL3-mediated methylation of mRNA on N6-adenosines as a dynamic modification that is enhanced in response to hypertrophic stimuli and is necessary for a normal hypertrophic response in cardiomyocytes. Overall design: To determine the role of m6A methylation in the heart we isolated primary cardiomyocytes and performed m6A immunoprecipitation followed by RNA sequencing.